Yes, fine, but every year millions of people get older without getting busy with the teacher after yoga class. So why is Marsha any different?

One theory: A 2014 study suggests we subconsciously attach significance to “nine-ender” years.

When we’re a year away from the odometer rolling over, we become more aware of the passage of time and youth, and we may do stupid things because we think the clock is running out.

What to Do About It
Fill up your calendar. Reflecting on what we have or haven’t achieved over the past decade can lead to bleak thoughts, says quality-of-life researcher Michael Steger, Ph.D.

So, be the man who makes things happen.

“If travel is important, you might plan a birthday trip that satisfies shared goals—like Hawaii if you’ve both wanted to try hiking a volcano.”
Bonus: When her mind’s on molten lava, the last thing she’ll be thinking about is her yoga instructor.

Why She Cheats: The Money
Emily, 35, had every reason to be furious with her husband. After she’d made a few too many purchases on her debit card, he cut up the plastic in front of her in a humiliating power play.

“I had to tell him where I was going and he would give me a spending limit,” she says.

The nice way to describe this: He was trying his best to keep the budget in check—and stepped about five miles over the line.

Problem is, exerting too much financial control, especially when you do it like a condescending jerk, breeds major-league resentment and can push your partner to seek payback, Hokemeyer says.

And that’s exactly what Emily did.

“A few months after that incident,” she says, “I slept with my high school boyfriend.”

What to Do About It
Don’t seize control or point fingers.
Instead, share the financial responsibility by using a budgeting app like Mint, which notifies both of you as spending limits draw near.

This way you’re both accountable for the money going into and coming out of your account.

Why She Cheats: She’s Expecting a Prince
You would hope your wife understands that perfect men don’t exist.

But then there’s “Kyle.”

He writes poems and sends flowers, and he seems so sensitive.

Guys like Kyle make women like Sarah, a 30-year-old dentist in North Carolina, second-guess their marriages.

When people expect perfection in a partner, it usually sets them up for long-term disappointment. That nugget of obvious wisdom came from a 2014 study published in the Journal of Experimental Social Psychology.

“He made my husband pale in comparison,” Sarah says. “I slept with him because I was convinced he could fill the voids in my life.”

Well, Kyle filled at least one of those voids, and shortly thereafter, Sarah and her husband landed in divorce court.

What to Do About It
You can’t be everything she wants, and you have to be okay with that—and so does she.

But you can become a little better than you are.
The next time you two are squabbling, try this trick: “Fights tend to take place in the past or in the present,” says Jay Heinrichs, author of Thank You for Arguing.

So switch to future tense instead.

“If you’re fighting about who makes dinner, say, ‘I’ll set up a cooking schedule if you’ll agree to eat eggs for dinner,’” he says.

You’ll never be Prince Charming, but at least you’re offering to cook the occasional omelet.

Why She Cheats: She Wants to Be Bad

When her marriage began to fray, Ali, a 25-year-old marketing assistant, found herself in bed with the kind of roughneck guy she’d always avoided.
“When I met him, it seemed inevitable that we’d have sex,” she says.

During peak fertility—when ovaries are primed to do the dirty mambo—a rational woman may find herself attracted to men she’d be terrified to see in a dark alley, says Vinita Mehta, Ph.D., the author of an upcoming book on dating and relationships.

Strength isn’t just about brawn. Demonstrate that you’re educated, successful, self-reliant, and commitment-oriented.

Mehta suggests finding more modern ways to display your plumage. Try sharing experiences that show your strengths—the theater, a museum, a trail hike.

She might think twice about putting her relationship at further risk with a one-night stand.

Why She Cheats: She Just Wants More
Who doesn’t want to be the guy who can’t go out in public without his wife leaning over and whispering, “I’m not wearing panties. Let’s go see if we can find an empty closet.”

But sometimes, in the real world, crazy sex isn’t everything it’s cracked up to be.

That’s how the trouble began for Lisa, a 31-year-old saleswoman. She wanted sex every night and her boyfriend didn’t.
“He only gave it to me once a week. What’d he expect?” she says of her stepping out.

Well, for starters, that you wouldn’t cheat on him. But when sexual expectations don’t match, it can quickly lead to trouble.

What to Do About It
The two biggest reasons women cheat, says sex researcher Debby Herbenick, Ph.D., are that they feel undesired or unattractive, especially as they become older.

S*x is one way to fix it, but another is to appreciate her for who she is, not who you want her to be.

Don’t insult her with meaningless compliments. Listen to her and validate who she really is.